Approximately 93 million miles away from Earth, the star we know as the Sun provides both the light and the heat which is required for life on this blue planet to exist. 99.8 percent of the entire mass of our solar system is contained in the Sun and the star is so massive that it takes up a space equivalent to about one million Earths. The energy given off by the Sun and the solar winds it creates shapes space weather across the solar system and its status as the closest star to Earth makes it a popular subject for scientific study to gain a greater understanding of the many other completely gaseous, extremely high-energy bodies which exist across the universe.
There is much that we currently understand about the Sun, including its average surface temperature, rotational speed and the activity of sunspots. However, the finer details of the Sun’s coronal atmosphere have remained hidden due to the incredible heat and radiation given off by the star. In the early morning hours of Saturday, August 11th, NASA plans to launch the Parker Solar Probe, a spacecraft that is outfitted with various scientific instruments meant to study the near-Sun environment. At its closest, the Parker probe will collect data at 3.8 million miles from the Sun where it will experience temperatures reaching 2,500°F.
Eugene Newman Parker, the Astrophysicist Who First Proposed Solar Winds
The namesake for the Parker probe is Eugene Newman Parker, an astrophysicist and professor emeritus at the University of Chicago. This honor is particularly immense given the fact that NASA has never before named a mission or spacecraft after a researcher who was still alive at the time of the naming.
Born in 1927, Parker graduated with his Ph.D. from Caltech in 1951 and first proposed his theory of solar winds in 1958. Parker theorized that a stream of charged particles escaping from the Sun was the cause of a wide range of electromagnetic interactions affecting the magnetic fields of planets throughout the solar system. Parker also devised scientific theories to explain the fact that the Sun’s surface, which reaches an average temperature of about 10,800°F, isn’t nearly as hot as the corona, which reaches temperatures of 900,000°F and higher.
When first proposed, Parker’s theories were viewed with great skepticism but scientific observations made over the years has by and large proven him to be correct. During his career, Parker has earned a great number of awards and recognitions for his work including the Chapman Medal (1987), National Medal of Science (1989) and the Kyoto Prize (2003).
Parker Probe’s Scientific Instruments to Unlock the Secrets of Solar Winds
The Parker Solar Probe is outfitted with a series of four suites of scientific instruments which includes the FIELDS scientific array developed by researchers at the Space Sciences Laboratory at the University of California, Berkeley. FIELDS uses five antennas, four of which extend beyond the heat shield and are fully exposed to the Sun, to measure electric fields and the properties of the solar winds. The four antennas exposed to the Sun measure the flow of particles traveling from the Sun and the fifth antenna, which is situated perpendicular to the other antennas, creates a three-dimensional picture of the electric field. FIELDS also measures magnetic fields with the use of three magnetometers: a search coil magnetometer which measures voltage to track magnetic field changes over time; and two flux magnetometers called MAGi and MAGo which measures magnetic fields further from the Sun where changes in the magnetic field are much slower.
The velocity, temperature and density of the particles making up the solar wind will be measured by the Solar Wind Electrons Alphas and Protons (SWEAP) investigation, jointly operated by Cambridge’s Smithsonian Astrophysical Observatory and the Space Sciences Laboratory at UC Berkeley. This instrument suite includes two tools. The Solar Probe Cup (SPC), a type of device also known as a Faraday cup, is fully exposed outside of the craft’s heat shield and includes a series of transparent grids above collector plates to collect charged particles shot out from the Sun in a vacuum. SWEAP also incorporates a pair of Solar Probe Analyzers (SPAN) known as SPAN-A and SPAN-B, both of which have wider fields of view than the SPC. Particles that enter these instruments are sent through deflectors and voltages to measure the mass and charge of the particles they collect.
Images of the corona and the solar atmosphere will be captured by the Wide-Field Imager for Parker Solar Probe (WISPR), designed by the Solar and Heliophysics Physics Branch at DC’s Naval Research Academy. WISPR takes images of coronal mass ejections with the use of two cameras that are contained within a housing which is about the size of a shoebox. Instead of imaging the Sun head-on, the camera is blocked behind the heat shield so that the cameras can better view structures in the corona. Each of WISPR’s cameras utilize radiation-hardened active pixel sensor complementary metal-oxide semiconductor (CMOS) detectors that are lightweight, energy-efficient and have a low susceptibility to both radiation and dust.
Finally, the lifecycle of particles ejected from the Sun will be measured by the Integrated Science Investigation of the Sun (IS?IS, pronounced “ee-sis”) which was designed and built and will be operated by a collection of organizations including Princeton University, Caltech, Johns Hopkins Applied Physics Laboratory, Southwest Research Institute, NASA’s Goddard Flight Center and the University of New Hampshire in Durham. IS?IS features two Energetic Particle Instruments (EPI) known as EPI-Lo and EPI-Hi. EPI-Lo is configured as an octogonal dome with 80 viewfinders about the size of a dime, each of which collects low-energy ions that pass through carbon-polyimide-aluminum foils that produce electrons when impacted by the ions; the energy left by the ions and the time needed to pass through the foils help EPI-Lo determine the composition of the particles. EPI-Hi has three particle sensors to measure high-energy particles. EPI-Hi’s sensors are stacked in layers of ultra-thin silicon detectors and charged particles are measured by how deep they penetrate into the detector layers at a rate of up to 100,000 particles per second.
Parker Probe Will Travel Faster Than Any Object Ever Made By Humans
Sending a spacecraft to any planetary object is a difficult feat of engineering but getting Parker to orbit the Sun is especially challenging given the need to cancel the sideways motion of planet Earth relative to the Sun. It’s also a very energy-intensive undertaking as NASA reports that traveling to the Sun requires 55 times the energy needed to travel to Mars.
However, it will not take long for Parker to reach the Sun as it’s expected that the craft will make its first perihelion, or point of orbit where it is closest to the Sun, on November 5th of this year. Prior to that, the Parker probe will perform a flyby of Venus in early October to assist the craft in its orbit. Parker will make seven Venus flybys over the course of seven years in a flight path designed to get the craft to more closely orbit the Sun over time.
The Parker Solar Probe will make a total of 24 orbits around the Sun through the year 2025 during the course of its scientific mission. At its closest approach, 3.83 million miles from the Sun, the probe’s speed will be around 430,000 miles per hour. At that speed, a person could travel from Philadelphia to Washington, D.C. in a single second. That speed will easily beat the previous record for a man-made object which was set in 2016 by the Juno spacecraft when it flew 165,000 MPH relative to Earth as that craft arrived at Jupiter.